Nattermann J, Nischalke H D, Feldmann G, Ahlenstiel G, Sauerbruch T, Spengler U
Department of Internal Medicine I, Rheinische Friedrich-Wilhelms-Universitaet, Bonn, Germany.
J Viral Hepat. 2004 Nov;11(6):519-26. doi: 10.1111/j.1365-2893.2004.00545.x.
Hepatitis C virus (HCV) infection has been shown to be associated with reduced expression of the CC chemokine receptor (CCR) 5, and reduced responsiveness of lymphocytes to chemokines. However, the mechanism by which HCV alters CCR5 expression remains unclear. Here, we investigated whether altered CCR5 expression in hepatitis C results from interactions of CD81 with the HCV E2 protein. Peripheral blood mononuclear cells (PBMC) from HCV-negative individuals were prepared by Ficoll density gradient separation. PBMC subpopulations (CD4+, CD8+ lymphocytes, CD19+ B cells, natural killer (NK) cells and monocyte-derived dendritic cells) were isolated and stimulated with immobilized HCV E2, and changes in CCR5 expression and CC-chemokine secretion were determined. Migration assays were performed using a 5-microm nitrocellulose filter microchamber system according to the manufacturer's recommendations. Exposure of PBMC to HCV E2 induced a dose-dependent release of regulated on activation normal T-cell-expressed and secreted (RANTES), down-regulation of CCR5 expression and intracellular accumulation of CCR5. This effect was blocked by preincubation of PBMC with anti-CD81. RANTES release following exposure to HCV E2 was mainly attributable to CD8+ cells. After exposure to HCV E2 markedly fewer CD8-positive lymphocytes were attracted by RANTES when compared with CD8+ cells that were studied in the absence of HCV E2. Our results suggest that interaction of HCV E2 with CD81 leads to increased RANTES secretion by CD8+ lymphocytes which induces down-regulation of CCR5 surface via receptor internalization resulting in altered lymphocyte migration.
丙型肝炎病毒（HCV）感染已被证明与CC趋化因子受体（CCR）5的表达降低以及淋巴细胞对趋化因子的反应性降低有关。然而，HCV改变CCR5表达的机制仍不清楚。在此，我们研究了丙型肝炎中CCR5表达的改变是否源于CD81与HCV E2蛋白的相互作用。通过Ficoll密度梯度分离法制备HCV阴性个体的外周血单核细胞（PBMC）。分离PBMC亚群（CD4 +、CD8 +淋巴细胞、CD19 + B细胞、自然杀伤（NK）细胞和单核细胞衍生的树突状细胞），并用固定化的HCV E2进行刺激，然后测定CCR5表达和CC趋化因子分泌的变化。根据制造商的建议，使用5微米硝酸纤维素滤膜微室系统进行迁移试验。PBMC暴露于HCV E2会诱导调节激活正常T细胞表达和分泌因子（RANTES）的剂量依赖性释放、CCR5表达的下调以及CCR5在细胞内的积累。用抗CD81预孵育PBMC可阻断这种效应。暴露于HCV E2后RANTES的释放主要归因于CD8 +细胞。与在未接触HCV E2情况下研究的CD8 +细胞相比，暴露于HCV E2后，被RANTES吸引的CD8阳性淋巴细胞明显减少。我们的结果表明，HCV E2与CD81的相互作用导致CD8 +淋巴细胞分泌的RANTES增加，进而通过受体内化诱导CCR5表面下调，从而导致淋巴细胞迁移改变。
